1. FIELD OF THE INVENTION
The present invention relates to a compressor unit and a separator therefor, and more particularly, to a compressor unit and a separator therefor which enable the arrangement of oil returning pipes to be simplified, and which are capable of eliminating any reduction in the discharge flow rate that might occur when the oil is returned.
2. DESCRIPTION OF THE PRIOR ART
In a conventional compressor unit, e.g., a helium gas compressor unit, oil cooled by a water-cooling or air-cooling type oil cooler is injected into a suction inlet or a hydraulic inlet of a compressor for the purpose of removing the compressive heat generated in the gaseous helium compressed by a compressor. The oil contained in the high pressure gaseous helium discharged from the compressor at a high concentration is therefore separated by a plurality of oil separators which are connected in series by pipes, the individual oil separators separating oil from gaseous helium at different ratios.
The above-described type of compressor unit has been proposed in, for example, the specification of Japanese Patent Publication No. 57-27992.
However, in the conventional techniques, no attention has been paid to any reduction in size of an oil separator. More specifically, a group of oil separators and an adsorber which are divided into individual oil separators and an adsorber are connected in series through pipes. In consequence, the overall size of the group of oil separators is large, and the pipes extend over a considerable distance, increasing the pressure loss. Further, the possibility of gas leaking between the oil separators and the pipes is high, while the number of man-hours required for manufacturing oil separators is increased. The same problems arise with respect to the removal of water content and solids contained in a gas other than gaseous helium and solids contained in the liquid.
In the conventional technique discussed in the passage from page 266 to page 268 of Low-Temperature Technology Vol 17, No. 5(1982), the oil separated by a plurality of oil separators provided on the downstream side of the discharge port of a compressor is returned to the suction side of the compressor through individual oil return pipes. This causes the fluid, e.g., gaseous helium discharged from the compressor to be returned to the low-pressure side together with the oil, greatly reducing the flow rate at which helium is discharged from the outlet of a compressor unit.